Telescope aboard the iss

why is there no telescope like hubble on the international space station/?
as i know, the iss is only 150 km lower in orbit than the hubble space telescope, and is at different inclination.
Having people around is pretty convenient i think, so replacing parts and doing regular maintenance would be easy, and cheaper as a main reason

My question is what is the reason for not being so?

Is there a financial problem?
or there are scientific reasons beyond my understanding connected with those 150 km of height,
or simply no one wants to have anything to do with the manned space program?
i think it would be a good thing, at least in the eye of the public , -the crew would have one more reason to be up there...

a good question, and altho I don't know a specific answer, I would suggest the biggest reason would be
a major lack of stability. The ISS is huge compared to Hubble and even if it was unmanned it would be a nightmare to stabilise
with humans bouncing around inside it all the time, the whole structure would be vibrating even more so

a good question, and altho I don't know a specific answer, I would suggest the biggest reason would be
a major lack of stability. The ISS is huge compared to Hubble and even if it was unmanned it would be a nightmare to stabilise
with humans bouncing around inside it all the time, the whole structure would be vibrating even more so

Dave

yes, never thought of that... although i think that's not unsolvable , given the cost reduction
perhaps it could be placed 10-100 m apart, close enough
thank you

You still have to make that other hubble and ship it to space - so the question is, once you do that, is there an advantage to docking it to the ISS instead of flying it standalone as other space telescopes (there's a whole menagerie of these : http://en.wikipedia.org/wiki/List_of_space_telescopes) ? You point to ease of maintenance by the crew (for operation, i don t think humans on board are a big advantage, even earth based telescopes are largely operated remotely) which is one, and to the publicity aspect for the ISS, but is it enough to justify other constraints this must imply ?

It would be interesting to find a mission where the advantages (e.g. flexibility to change elements such as upgrading detectors after launch etc.) would make the ISS docking option a clear winner. Hubble was maintained on-site after launch but this must be much cheaper to do using the ISS logistics.

One detail, the ISS must be a somewhat noisy environnement with various sources of vibration, so I wonder if a scope docked there might need extra care to isolate the telescope from that, or maybe just tethering instead of rigid docking - or best just have the scope orbit a short distance from the ISS and walk there when needed.

It seems like to me that the major disadvantage to this would be all the "stuff" that's jettisoned from ISS could interfere with a mounted telescopes operation. The inclination is also a factor, as well the vibrations other people have mentioned. I think you would also have to consider that there is more atmosphere at the ISS altitude, which could affect pointing. It could probably be done, but the ISS set to burn up sometime in 2020 unless it's extended, I don't think you'd see much benefit.

I believe I've read that stability is the overwhelming factor in why this is not a good idea. Minor bumps against any part of the ISS by a crew member cause too much vibration for something that sensitive (it blurs the image) and also there are motors and things in the ISS that cause vibration. When you're looking at something 13+billion light years away (see "Hubble Deep Field") the most trivial change in viewing angle and you're looking at a different galaxy.